greenhomesums
Air source heat pump cost UK — running cost calculator + is it worth it?
Air source heat pump cost UK: £8,000–£14,000 installed, £7,500 BUS grant available. Calculate running cost vs gas boiler and 15-year total cost of ownership. Updated for 2026.
Air source heat pump cost UK (2026)
A fully installed air source heat pump costs £8,000–£14,000 in the UK in 2026. The £7,500 Boiler Upgrade Scheme grant reduces net cost to £500–£6,500 for eligible homes in England and Wales.
| Home size | Unit size | Gross install cost | After BUS grant |
|---|---|---|---|
| 1–2 bed flat / terrace | 5–7 kW | £8,000–£10,000 | £500–£2,500 |
| 3-bed semi (average UK home) | 8–10 kW | £9,000–£12,000 | £1,500–£4,500 |
| 4–5 bed detached | 12–14 kW | £11,000–£14,000 | £3,500–£6,500 |
| + radiator upgrades (if needed) | — | add £1,500–£3,000 | not grant-covered |
Running cost depends on your insulation level and tariff. A typical 3-bed semi achieves SCOP 3.3 on the Ofgem cap, costing around £980/yr in electricity for heat — versus £800/yr for gas. On Octopus Cosy that gap closes to near zero. Enter your details in the calculator below for a personalised figure.
Always get at least three quotes from MCS-certified installers. Costs vary significantly — quotes above £14,000 for a standard semi are rarely competitive.
Is a heat pump worth it in the UK?
For most UK homes with average or better insulation and the £7,500 Boiler Upgrade Scheme grant, yes — over a 15-year view. A heat pump typically costs slightly more to run per year than a gas boiler at current prices, but the grant plus avoided boiler replacement (£2,500–£3,500 every 12–15 years) puts most homes ahead by year 8–10, saving £3,000–£8,000 over 15 years.
The three conditions that make a heat pump worth it:
- EPC D or better — average insulation is sufficient; EPC F/G homes need insulation first
- Eligible for the £7,500 BUS grant (England and Wales homeowners replacing fossil-fuel heating)
- Planning a 10+ year horizon — the 15-year total cost is where the heat pump wins, not year one
| Home type | Extra annual running cost vs gas | 15-yr net saving (with grant) | Verdict |
|---|---|---|---|
| Well-insulated (EPC B/C) | +£50–150/yr | ~£6,000–£8,000 | Worth it |
| Average insulation (EPC D) | +£200–350/yr | ~£3,000–£5,000 | Worth it |
| Average insulation + Cosy tariff | -£100–200/yr (cheaper) | ~£5,000–£7,000 | Strongly worth it |
| Poor insulation (EPC E), no grant | +£500–800/yr | ~-£1,000–£2,000 | Not worth it yet |
| Uninsulated (EPC F/G) | +£900–1,400/yr | Negative | Insulate first |
Enter your home details in the calculator below for a figure specific to your property. Running costs based on Ofgem cap effective 1 April 2026.
Interactive heat pump vs gas boiler calculator
Worked example
A typical 3-bedroom UK semi with average insulation, using the current Ofgem default tariff (electricity ≈ 27.03p/kWh, gas ≈ 6.04p/kWh), a £7,500 Boiler Upgrade Scheme grant, and a SCOP of 3.3:
Based on Ofgem price cap effective 1 April 2026.
| Heat demand | 13000 kWh/yr |
|---|---|
| Gas annual cost | £1038 |
| Heat pump annual cost | £1287 |
| Annual saving | £-249 |
| Heat pump net install (after BUS grant) | £3500 |
| Break-even year | 19.6 yrs |
| 15-yr net benefit vs gas | £-1834 |
You'll probably want this next
Heat pump looks worth it? Check the £7,500 grant
The Boiler Upgrade Scheme covers up to £7,500 of install cost — see if you qualify.
Check BUS grant eligibility →Heat pump running cost in your city
Want a city-specific figure without filling in the form? Browse our heat pump running cost hub — 50+ UK cities ranked by annual running cost for a typical 3-bed semi, with regional degree-day multipliers.
Frequently asked questions
- What is SCOP and why does it matter?
- SCOP — Seasonal Coefficient of Performance — is the ratio of heat delivered to electricity used, averaged over a UK heating season. A SCOP of 3.3 means you get 3.3 kWh of heat for every 1 kWh of electricity. A well-insulated home with a correctly-sized heat pump typically achieves 3.5–4.0; a poorly-insulated home or an undersized system can drop below 3.0. Fabric-first is the lever here — run our [insulation savings calculator before you commit to a heat-pump size.
- How big is the Boiler Upgrade Scheme grant?
- The UK government's Boiler Upgrade Scheme (BUS) offers £7,500 off the cost of an air-source heat pump for homes in England and Wales, paid directly to your MCS-certified installer. The grant is deducted from the quoted price — you never handle the money yourself. Confirm your property qualifies with our [Boiler Upgrade Scheme grant eligibility calculator.
- How accurate is the running-cost estimate?
- The calculation is based on the Ofgem default-tariff price cap and a SCOP derived from your insulation level. Real bills typically land within ±15% of the estimate. On a time-of-use tariff designed for heat pumps (e.g. Octopus Cosy), the heat pump running cost can be 20–30% lower than shown — see our [Octopus Agile savings calculator for the per-half-hour view. When the cap changes quarterly, use the [Ofgem price cap impact calculator to refresh the baseline.
- When is a heat pump NOT cheaper than a gas boiler?
- At current Ofgem prices (electricity ≈ 27p/kWh, gas ≈ 6p/kWh), a heat pump needs a SCOP of roughly 4.5 just to break even on per-unit energy cost. Most homes with average insulation achieve a SCOP of 3.0–3.5. A heat pump often loses on annual running cost alone, but wins on the 15-year total cost — because the £3,500 gas-boiler replacement every 15 years and the BUS grant tip the balance. In a poorly-insulated home with no grant, the gas boiler stays ahead. Size your unit honestly with our [heat loss calculator — oversized heat pumps cycle inefficiently and torpedo the SCOP.
- Is a heat pump worth it in 2026?
- For most UK homes, yes — but the case rests on the £7,500 Boiler Upgrade Scheme grant and a 15-year view, not annual running cost alone. At current prices (electricity ~27p/kWh, gas ~6p/kWh), a SCOP-3.3 heat pump costs slightly more to run per year than a gas boiler — but after the BUS grant and avoided boiler replacement (£2,500–£3,500 every 12–15 years), most average-insulated homes break even by year 8–10 and save £3,000–8,000 over 15 years. If you're also switching to a heat-pump-friendly tariff like Octopus Cosy, running costs drop a further 20–25% and the case strengthens considerably.
- Is an air source heat pump worth it in the UK?
- Air source heat pumps (ASHPs) are the practical choice for the vast majority of UK homes — ground source is more efficient but requires significant land and higher install cost (£15,000–£35,000 vs £8,000–£14,000 for air source). An ASHP is worth it if your home has average or better insulation, you can access the £7,500 BUS grant, and you're willing to take a 15-year view. The homes where it clearly isn't worth it: EPC F or G with no insulation budget, properties with no outdoor space for the unit, and homes sold within 5 years of install. Use the calculator above to run your specific numbers.
- Why are heat pumps not worth it for some UK homes?
- Three situations where the maths doesn't work. First, poorly-insulated homes: a SCOP below 2.8 (common in uninsulated solid-wall properties) means running costs exceed a gas boiler — insulation must come first. Second, no BUS grant eligibility: Scotland, Northern Ireland, new-builds and social housing don't qualify for BUS; without the £7,500 offset the payback stretches past 15 years for most. Third, the current electricity-to-gas price ratio: at 4.5:1, the UK penalises electrification more than most of Europe — if you have a very efficient gas boiler and poor insulation, the running-cost gap is real. The 15-year total-cost view (with grant and avoided boiler replacement) closes this gap for most homes, but not all.
- How much does an air source heat pump cost in the UK?
- An air source heat pump costs £8,000–£14,000 fully installed in the UK in 2026, before the £7,500 Boiler Upgrade Scheme grant. After the grant, net cost is typically £500–£6,500 depending on home size and system complexity. A 3-bed semi with average insulation usually needs an 8–10 kW unit; a larger detached home may need 12–14 kW. Costs vary significantly by installer — get at least three MCS-certified quotes. The grant is deducted at source by the installer; you never handle the money. Use the [BUS grant eligibility calculator to confirm your property qualifies before committing.
- What is the running cost of an air source heat pump in the UK?
- Running cost depends on your heat demand, SCOP and electricity tariff. A typical 3-bed semi using 12,000 kWh of heat per year, with a SCOP of 3.3 on the Ofgem cap (27p/kWh), costs around £980/yr to run versus £800/yr for the same heat from gas at 6p/kWh — a gap of about £180/yr. On Octopus Cosy or a heat-pump-friendly TOU tariff that gap closes to near zero or reverses. Enter your home details in the calculator above for a personalised running cost figure against your current gas boiler.
How this calculator works
The Heat Pump vs Gas Boiler calculator compares the running cost and 15-year total cost of ownership of an air-source heat pump against keeping your existing (or replacing a dying) gas boiler. The running-cost side is straightforward arithmetic: your heat demand in kWh per year, divided by SCOP for the heat pump path, multiplied by the current Ofgem cap electricity unit rate, plus standing charges — versus the same heat demand divided by boiler efficiency (we assume 90% for a condensing boiler that is properly commissioned), multiplied by the gas unit rate, plus gas standing charges. The 15-year view then adds install cost, applies electricity and gas inflation, and nets off the £7,500 Boiler Upgrade Scheme grant on the heat pump side.
Heat demand itself comes from one of two paths. If you know your annual gas use in kWh (look at the last 12 months on your bill), we use that directly and assume ~90% of it turns into useful space and water heat. If you don't, we use an archetype table indexed on property type, bedrooms and insulation level — built from MCS typical heat-loss figures and cross-checked against DESNZ housing-stock averages. SCOP — Seasonal Coefficient of Performance — is the single most important variable on the heat pump side; we default it from your insulation level (3.0 for poor, 3.3 for average, 3.8 for good) in line with the typical range reported by the MCS installer database.
Common pitfalls and things people get wrong
- SCOP is not COP. Manufacturers quote COP (Coefficient of Performance) at a single mild test point — often 4.5 at 7°C outdoor, 35°C flow. SCOP is the weighted-average performance across a real UK heating season, and is typically 20–30% lower. A heat pump sold as "COP 4.5" usually delivers SCOP 3.2–3.5 in an average UK home. Ask your installer for the MCS-calculated SCOP for your property, not the nameplate COP.
- Radiator sizing. Heat pumps run most efficiently at low flow temperatures (35–45°C). Existing radiators sized for a 70°C gas boiler are often undersized for that flow temperature, which forces the pump to run hotter and drops SCOP. A decent installer will model every room; a bad one will quote without looking. Budget £1,500–£3,000 for radiator upgrades on a typical 3-bed semi if your existing system was sized tight.
- Poorly-insulated homes. A heat pump in a leaky, single-glazed Victorian terrace with SCOP 2.6 can cost more to run than the gas boiler it replaces. Insulation first, heat pump second — the BUS grant rules actually encode this, requiring your EPC insulation recommendations to be cleared. Landlords facing the 2028 deadline should also check our MEES compliance calculator , which models insulation + heat pump as a combined stack.
- Planning and noise. Since 2024 most UK heat pump installations are permitted development under relaxed rules (1 metre from boundary, below the noise threshold). Listed buildings and some conservation areas still need planning consent. Modern units run at 40–45 dB at 1 metre — quieter than a fridge — but do check your boundary distance.
- Time-of-use tariffs change the answer. A tariff like Octopus Cosy gives you cheap electricity in three windows that align with heat-pump heating schedules; it can cut running cost 20–30% below the flat Ofgem cap this calculator assumes. If you are committed to a heat pump, factor that in rather than judging on the cap alone — our Octopus Agile calculator models what a shifting-willing heat-pump home does on a dynamic tariff.
UK-specific context
The UK is an outlier among wealthy countries in how cheap gas is relative to electricity. The electricity-to-gas unit-rate ratio sits near 4.5:1 on the Ofgem cap, which is why SCOP has to be around 4.5 for energy-parity on running cost alone. The policy lever here is the "spark gap": successive governments have talked about rebalancing levies off electricity and onto gas, which would tip the running-cost maths firmly in favour of heat pumps. In the meantime, the 15-year total-cost view — boiler replacement every 15 years, £7,500 BUS grant, longer heat-pump lifespan — is what makes the economics work today for most homes that aren't uninsulated.
On carbon: UK grid electricity in 2026 averages around 180 gCO₂/kWh and is falling about 8% per year; natural gas is 203 gCO₂/kWh at the meter and does not change. A SCOP-3.3 heat pump therefore emits about one-third of the CO₂ of the gas boiler it replaces — today — and that gap widens every year as the grid decarbonises. The running-cost table in this calculator does not show CO₂ directly, but it is the biggest reason to install even when the pound-notes case is tight.
When this isn't the right answer
Don't use this calculator to decide for a flat without outdoor wall or balcony space for an outdoor unit — that's a hybrid or district-heat conversation. Don't use it if your gas boiler is under 5 years old and working well; payback restarts from zero on a new install. And if your property is truly uninsulated (no loft, no cavity, single glazing), the honest answer is insulate first — a heat pump into that house has a SCOP around 2.5 and will disappoint. This calculator models a reasonable, improvable UK home; it doesn't model edge cases.
When a heat pump is not worth it
The economics tip against a heat pump in these situations:
- Poor insulation with no budget to improve it. A SCOP below 2.8 — typical in an uninsulated solid-wall property — means running costs exceed a gas boiler. The insulation savings calculator shows the cheapest path to getting walls and loft to a standard where a heat pump makes sense. The BUS grant actually encodes this: outstanding EPC insulation recommendations block eligibility until cleared.
- No BUS grant eligibility. Scotland and Northern Ireland have separate schemes (Home Energy Scotland, NI Direct); new-builds and social housing are excluded from BUS. Without the £7,500 offset, payback stretches past 15 years for most average-insulated UK homes. Check eligibility with the BUS grant calculator before committing.
- Gas boiler under 5 years old and working well. The avoided boiler replacement is a major part of the 15-year case. If your boiler is new, that clock resets — the financial case weakens significantly and it makes more sense to wait until the boiler is approaching end of life.
- No outdoor space for a unit. Air source heat pumps need an outdoor unit (roughly the size of a large suitcase). Flats without a balcony, garden or external wall access are not suitable for ASHP. A hybrid heat pump (gas backup) or district heating is the alternative.
- Short-term ownership. The upfront cost after the BUS grant is typically £6,000–£12,000 net. If you plan to sell within 5 years, it is unlikely you will recoup the net cost in sale price, though EPC uplift helps with the green mortgage discount .
Related calculators
Ranked by topic overlap with this tool.
- Boiler Upgrade Scheme Grant Calculator UK — Check eligibility for the £7,500 BUS heat pump grant and see your net install cost.
- MEES Landlord Compliance Calculator UK — Landlord-focused MEES compliance check with cheapest-first measure stack and grant offsets.
- EPC Band Upgrade Cost Calculator UK — Cost of raising your EPC to band C, B or A — measure stack, grants, resale uplift and green-mortgage saving.
- Holiday-Let EPC Upgrade Calculator UK — Holiday-let EPC upgrade cost, occupancy-weighted running-cost saving, comfort-premium revenue uplift, and FHL capital allowance notes.
- Heat Loss Calculator UK — Heat Pump Sizing — Whole-house heat loss in kilowatts — the number that sets your heat pump size, radiator upgrades and BUS grant headroom.